Search Publications

Saturn's latitudinal C ₂H ₂ and C ₂H ₆ abundance profiles from Cassini/CIRS and ground-based observations

Fletcher, Leigh N.; Nixon, Conor A.; Achterberg, Richard K. +8 more

Hydrocarbons in the upper atmosphere of Saturn are known, from Voyager, ground-based, and early Cassini results, to vary in emission intensity with latitude. Of particular interest is the marked increase in hydrocarbon line intensity near the south pole during southern summer, as the increased line intensity cannot be simply explained by the incre…

Two More Disk Galaxies with Global Gas Counterrotation

Moiseev, A. V.; Sil'chenko, O. K.; Afanasiev, V. L.

We report a discovery of extended counterrotating gaseous disks in early-type disk galaxies NGC 2551 and NGC 5631. To find them, we have undertaken complex spectral observations including integral-field spectroscopy for the central parts of the galaxies and long-slit deep spectroscopy to probe the external parts. The line-of-sight velocity fields …

Solar Magnetic Field Signatures in Helioseismic Splitting Coefficients

Basu, Sarbani; Antia, H. M.; Baldner, Charles S. +1 more

Normal modes of oscillation of the Sun are useful probes of the solar interior. In this work, we use the even-order splitting coefficients to study the evolution of magnetic fields in the convection zone over solar cycle 23, assuming that the frequency splitting is only due to rotation and a large-scale magnetic field. We find that the data are be…

Dipolar Evolution in a Coronal Hole Region

Yang, Shuhong; Zhang, Jun; Borrero, Juan Manuel

Using observations from the Solar and Heliospheric Observatory, the Solar Terrestrial Relations Observatory, and Hinode, we investigate magnetic field evolution in an equatorial coronal hole region. Two dipoles emerge one by one. The negative element of the first dipole disappears due to the interaction with the positive element of the second dipo…

The scientific rationale for the C1XS X-ray spectrometer on India's Chandrayaan-1 mission to the moon

Grande, M.; Koschny, D.; Rothery, D. A. +23 more

The UK-built Chandrayaan-1 X-ray Spectrometer (C1XS) will fly as an ESA instrument on India's Chandrayaan-1 mission to the Moon, launched in October 2008. C1XS builds on experience gained with the earlier D-CIXS instrument on SMART-1, but will be a scientifically much more capable instrument. Here we describe the scientific objectives of this inst…

Infrared limb sounding of Titan with the Cassini Composite InfraRed Spectrometer: effects of the mid-IR detector spatial responses

Nixon, Conor A.; Flasar, F. Michael; Teanby, Nicholas A. +8 more

Does a Polar Coronal Hole's Flux Emergence Follow a Hale-Like Law?

Golub, L.; DeLuca, E. E.; Savcheva, A. +1 more

Recent increases in spatial and temporal resolution for solar telescopes sensitive to EUV and X-ray radiation have revealed the prevalence of transient jet events in polar coronal holes. Using data collected by the X-Ray Telescope on Hinode, Savcheva et al. confirmed the observation, made first by the Soft X-ray Telescope on Yohkoh, that some jets…

Reconstructed and measured total solar irradiance: Is there a secular trend between 1978 and 2003?

Solanki, S. K.; Krivova, N. A.; Wenzler, T.

Total solar irradiance reconstructed between 1978 and 2003 using solar surface magnetic field distributions is compared with three composites of total solar irradiance measurements. A good correspondence is found with the total solar irradiance composite from PMOD/WRC, with no bias between the three cycles. The agreement with the other composites …

Poleward arcs of the auroral oval during substorms and the inner edge of the plasma sheet

Haerendel, Gerhard

An analytical model for the connection between the near-Earth edge of the plasma sheet at substorm onset and the auroral arcs at the poleward edge of the auroral oval is presented. The connection is established through the existence of a Boström type I current system. Its generator is assumed to be constituted by a narrow high-beta plasma layer lo…

Suzaku Observations of SGR1900+14 and SGR1806-20

Yonetoku, D.; Mihara, T.; Yamaoka, K. +8 more

Spectral and timing studies of Suzaku ToO observations of two SGRs, 1900+14 and 1806-20, are presented. The X-ray quiescent emission spectra were well fitted by a two blackbody function or a blackbody plus a power law model. The non-thermal hard component discovered by INTEGRAL was detected by the PIN diodes and its spectrum was reproduced by the …